Merge pull request #26 from xmltechgeek/add-globals

Is there a way to define my own helper functions/external globals for nools files?

lib/parser/nools/tokens.js

@@ -141,6 +141,29 @@ module.exports = {
         }
     },
 
+	"global": function (orig, context) {
+		var src = orig.replace(/^global\s*/, "");
+		var name = src.match(/^([a-zA-Z_$][0-9a-zA-Z_$]*\s*)/);
+		if (name) {
+			src = src.replace(name[0], "").replace(/^\s*|\s*$/g, "");
+			if (utils.findNextToken(src) === "=") {
+				name = name[1].replace(/^\s+|\s+$/g, '');
+				var fullbody = utils.getTokensBetween(src, "=", ";", true).join("");
+				var body = fullbody.substring(1, fullbody.length - 1);
+				body = body.replace(/^\s+|\s+$/g, '');
+				context.scope.push({name: name, body: body});
+				src = src.replace(fullbody, "");
+				return src;
+			}
+			else {
+				throw new Error("unexpected token : expected : '=' found : '" + utils.findNextToken(src) + "'");
+			}
+		}
+		else {
+			throw new Error("missing name");
+		}
+	},
+
     "function": function (orig, context) {
         var src = orig.replace(/^function\s*/, "");
         var name = src.match(/^([a-zA-Z_$][0-9a-zA-Z_$]*)\s*/);

readme.md

@@ -26,6 +26,7 @@ Or [download the source](https://raw.github.com/doug-martin/C2FO/master/nools.js
       * [Structure](#rule-structure) 
       * [Constraints](#constraints)
       * [Actions](#action)
+      * [Globals](#globals)
    * [Browser Support](#browser-support)
    * [Fibonacci](#fib)
 
@@ -586,6 +587,26 @@ then {
 
 For rules defined using the rules language nools will automatically determine what parameters need to be passed in based on what is referenced in the action.
 
+<a name="action"></a>
+
+### Globals
+
+Globals are accessible through the current working scope in your rules runs from the nools rules format. Note that globals are not part of the working
+memory so are not accessible during the when portion of your rules run. Globals are used like the following:
+
+```
+global util = require('util');
+
+rule "A Rule" {
+    when {
+    	$obj: Object;
+    }
+    then{
+    	util.log("Hello Globals :)");
+    }
+}
+```
+
 ## Emitting custom events.
 
 You may also emit events from your rule actions using the sessions emit function.

test/noolsParser.test.js

@@ -32,6 +32,12 @@ it.describe("nools dsl parser",function (it) {
             });
         });
 
+		it.should("parse a global statement", function () {
+			var parsed = noolsParser.parse("global util = require('util');");
+			assert.equal(parsed.scope[0].name, 'util');
+			assert.equal(parsed.scope[0].body, "require('util')");
+		});
+
         it.should("throw an error when the define block is missing a name", function () {
             assert.throws(function () {
                 noolsParser.parse("define {myProp : 'value'");
@@ -46,6 +52,18 @@ it.describe("nools dsl parser",function (it) {
                 noolsParser.parse("define Test myProp : 'value'}");
             });
         });
+
+		it.should("throw an error when the global statement is missing a name", function () {
+			assert.throws(function () {
+				noolsParser.parse("global = require('util');");
+			});
+		});
+
+		it.should("throw an error when the global statement is missing a ;", function () {
+			assert.throws(function () {
+				noolsParser.parse("global util = require('util')");
+			});
+		});
     });
 
     it.describe("parsing function", function (it) {

test/rules/scope.nools

@@ -9,11 +9,14 @@ function matches(str, regex){
     return regex.test(str);
 }
 
+global util = require('util');
+
 rule Hello {
     when {
         m : Message matches(m.message, /^hello(\\s*world)?$/);
     }
     then {
+    	util.log("Hello Globals :)");
         modify(m, function(){
             this.message += " goodbye";
         })